{% set class = "md-tabs" %}{% if page.ancestors | length > 0 %}  {% set class = "md-tabs md-tabs--active" %}{% endif %}<nav class="{{ class }}" data-md-component="tabs">  <div class="md-tabs__inner md-grid">    <ul class="md-tabs__list">      {% for nav_item in nav %}        {% include "partials/tabs-item.html" %}      {% endfor %}    </ul>  </div></nav>